Big Boy Posted October 17, 2009 Report Share Posted October 17, 2009 Could some one please help recomend what will be the best bore on my stock carbs! I now have a 420 big bore, Dune port, T-5's, boost bottle, intake, Cool heads with 18cc domes. I've done some research and it seams that a 28mm oval to a 30mm seams to be the genral consensus! I'm not looking to spend alot of money on new carbs and would really like to just use my stock if possible! Quote Link to comment Share on other sites More sharing options...
blowit Posted October 17, 2009 Report Share Posted October 17, 2009 Could some one please help recomend what will be the best bore on my stock carbs! I now have a 420 big bore, Dune port, T-5's, boost bottle, intake, Cool heads with 18cc domes. I've done some research and it seams that a 28mm oval to a 30mm seams to be the genral consensus! I'm not looking to spend alot of money on new carbs and would really like to just use my stock if possible! Stock carb is a 26mm and is bore limited by the diameter of the slide valve which is 27.50mm. Regardless of what you read, you cannot take them past that point or they will have a nasty air bypass condition that is sure to give you huge headaches. We have stopped boring the Banshee carbs because the return for our customers just is not there unless racing in a specific class that requires stockers. You can apply some taper boring or venturi work on the back but we decided to develop a venturi intake/filter kit instead as it was hitting several birds with one stone. Brandon Mull Engineering Quote Link to comment Share on other sites More sharing options...
Big Boy Posted October 17, 2009 Author Report Share Posted October 17, 2009 (edited) Thank you for your in put Brandon! I feel like i'm just missing something in the power i think i should have! Maybe it's just never enough but i don't think that that's it! Is there anything you would recomend for a little more power but not to expensive! And do you think that i will be able to feel a difference after installing the intake system that you told me about! Edited October 17, 2009 by Big Boy Quote Link to comment Share on other sites More sharing options...
scottd480 Posted October 17, 2009 Report Share Posted October 17, 2009 Thank you for your in put Brandon! I feel like i'm just missing something in the power i think i should have! Maybe it's just never enough but i don't think that that's it! Is there anything you would recomend for a little more power but not to expensive! And do you think that i will be able to feel a difference after installing the intake system that you told me about! Try picking up a pair of 30mm OKO carbs...great bang for the buck, and you can usually get them for around $200 new. Quote Link to comment Share on other sites More sharing options...
blowit Posted October 18, 2009 Report Share Posted October 18, 2009 Thank you for your in put Brandon! I feel like i'm just missing something in the power i think i should have! Maybe it's just never enough but i don't think that that's it! Is there anything you would recomend for a little more power but not to expensive! And do you think that i will be able to feel a difference after installing the intake system that you told me about! I will say that tuning is everything on carbs and probably 50% of bikes out there are missing some serious power due to tuning issues. I am not sure what you are running now for an intake kit but I know we have never found anything else that will flow more air than our kit on stock carbs. They breath the same as a 29mm carb IIRC with the kit installed. Bigger carbs are always a consideration but many people like to keep the responsiveness of the stock carbs. Brandon Quote Link to comment Share on other sites More sharing options...
patrickkomar Posted October 18, 2009 Report Share Posted October 18, 2009 (edited) wow I'm impressed So is this a good upgrade for some one running stock porting? How will these hold up on a dune bike running on rough sand with a 6 over swinger?I guess what i'm getting at is how floppy are they hanging way back there? do you have outerwears in stock for these filters? Edited October 18, 2009 by patrickkomar Quote Link to comment Share on other sites More sharing options...
blowit Posted October 18, 2009 Report Share Posted October 18, 2009 wow I'm impressed So is this a good upgrade for some one running stock porting? How will these hold up on a dune bike running on rough sand with a 6 over swinger?I guess what i'm getting at is how floppy are they hanging way back there? do you have outerwears in stock for these filters? We have never had anyone lose a set. I run them in the dunes all the time. We use a very heave clamp kit. You would be surprised how rigid they are. I do not sell the outerwears for these because we have learned that they actually cause more problems than they prevent and we have 2x the number of pleats on the filters to work better for off road use. If you really want outerwears, they are available in this filter size from outerwears. Brandon Quote Link to comment Share on other sites More sharing options...
patrickkomar Posted October 18, 2009 Report Share Posted October 18, 2009 ok I'll bite....... what problems do outerwears present? Quote Link to comment Share on other sites More sharing options...
blowit Posted October 18, 2009 Report Share Posted October 18, 2009 ok I'll bite....... what problems do outerwears present? They reduce flow approx 10% when clean but can be as much as 50% restrictive when dirty. If any moisture hits them at all, They plug up. We have had big problems with riders in wet grass. The pore network of a gauze filter allows decent flow when dirty compared to the outerwear. Brandon Quote Link to comment Share on other sites More sharing options...
patrickkomar Posted October 18, 2009 Report Share Posted October 18, 2009 (edited) That makes total sense to me but what about some one like me who rides sand only? Bare oiled filters in the sand would be covered quick I would think. In my case do you think they would still do more harm than good? Edited October 18, 2009 by patrickkomar Quote Link to comment Share on other sites More sharing options...
blowit Posted October 19, 2009 Report Share Posted October 19, 2009 That makes total sense to me but what about some one like me who rides sand only? Bare oiled filters in the sand would be covered quick I would think. In my case do you think they would still do more harm than good? In our experience, the oils from the filter and the moisture from sand can eb enough to cause issues. Honestly, if the outerwear if cleaned religiously, it works as designed but many people ignore them and don;t realize the power being lost. Brandon Quote Link to comment Share on other sites More sharing options...
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